Thank you for your honesty regarding your hydroponic experiment.
As I no doubt poorly tried to communicate in the Homesteading Challenge #6 Nature is often our best teacher. With "hydroponics" there is a model in nature that we call a swamp or pond.
The quick takeaway is that we see nutrient rich water flowing into a contained space that contains plants created to grow in a water medium. A benthic zone develops which functions similarly to a healthy soil on land. This zone maintains the balance (with all the little creatures that live there so keep them happy) that allows aquatic plants to thrive. Some terrestrial plants can be suspended in floating containers in the healthy water and will thrive. By floating they are protected from land-bound pests, but not flying pest or diseases exacerbated by a mono-culture. If you add fish you also add nutrients to the pond and other controls. Just make sure they aren't vegetarian fish. ;-)
The oriental cultures have been employing this polyculture approach for centuries with great success.